Cost-Benefit Analysis (CBA) of Sustainable Drainage Systems (SUDS) Retrofit: a Case Study

Abstract

The retrofit of Sustainable Drainage Systems (SuDS) has been applied successfully to properties to help mitigate future flooding and to deliver other benefits to properties, such as improvements in air and water quality, economic benefits and improved business reputation. However, the uptake of SuDS retrofit has been low due to a lack of understanding of the true costs and benefits and concerns about long-term maintenance. This study presents a cost-benefit analysis (CBA) of the monetary and non-monetary values of SuDS retrofit in the context of an individual property, in this case, a leisure centre. A qualitative study was carried out comprising a series of interviews with stakeholders to the property, an analysis of documentary evidence and observations on the site. The findings demonstrate the importance of teamwork amongst the stakeholders during the decision-making process in helping to overcome many of the known challenges. The willingness to pay process is used to value the tangible and intangible benefits arising from the scheme. The installation would provide a net value to the client of well over £100,000 over a 10-year period versus the installation costs of £39,000 and the return on investment would be achieved in just 3 years. The findings highlight many of the apparent barriers that need to be overcome when installing retrofit schemes and clearly demonstrate the importance of the intangible benefits derived. It is recommended that these are given full consideration at the decision-making stage and in supporting the uptake of the retrofit of SuDS.

Retrofitting Sustainable Urban Drainage Systems (SuDS): A Cost-Benefit Analysis Appraisal

“…Since consumers are usually faced with the need to solve a major flooding event that may have invaded their property, it is usually a huge commitment to decide on the implications of investing in a scheme or other available alternatives to mitigate the effect of flooding events. This process is largely characterised by extended problem solving and CBA considerations, which have been expressed in the details of earlier research conducted by the authors [45].…”